After days of buildup amid a political firestorm, House Republicans released a controversial memo on Friday that alleges the FBI abused its surveillance authority to target a former foreign policy adviser to the Trump campaign.

The memo also has shed more light on the broader Russia case and confirmed or advanced other aspects of the story beyond the GOP's campaign against the FBI and Department of Justice.

The FBI clashed with the White House on Wednesday over the much discussed Republican memo that alleges the bureau abused its surveillance powers. The bureau said it has "grave concerns" about the "accuracy" of the document that the president supports making public.

Meanwhile, the ranking Democrat on the House intelligence committee, which voted to release the memo, says Republicans secretly made "material changes" to the document after the decision to make it public.

FBI deputy director Andrew McCabe is leaving the bureau after more than 20 years on the job, according to an individual familiar with the matter.

McCabe stepped down Monday from his post as the bureau's No. 2 official, and as expected he will take accumulated leave and remain on the payroll until March when he is eligible to retire with full benefits. The departure plan had been in the works for a while.